Automated, high-volume currency processing is a growing international industry affecting numerous aspects of the distribution, collection, and accounting of paper currency. Currency processing machines can be designed to detect numerous features of currency notes that pass several detectors on a conveyor in order to sort the currency and identify counterfeit or reject notes. For example, prior art currency processing machines are capable of detecting various physical characteristics of notes such as soiling level, optical quality, rips and tears, and can quantify missing portions of the notes. Data collected by detecting one or more of these physical characteristics can be compared to a set fitness standard when determining if an individual note should be rejected, and thereby taken out of circulation, or sorted for future distribution.
Currency notes are typically embedded with fibers, for example cotton fibers and wood pulp, giving the note a certain level of rigidity or stiffness. As the note is placed in circulation and manipulated while in use, the fibers gradually breakdown and the note loses its rigidity, or, conversely, the limpness of the note increases with use. Limp notes pose a number of problems in commerce. For example, limp notes can jam or tear in automatic currency handling devices. Likewise, torn currency poses a problem for merchants who do not want to risk accepting currency that is not negotiable. It may be more difficult to detect counterfeit notes from authentic currency if the notes are badly worn and limp. Therefore, a need exists for a method of testing currency for limpness. By developing a method for determining the limpness of a single note, a currency processing machine could be used to incorporate this method with other tests for physical characteristics of a note to more accurately determine if a note should be pulled from circulation. The single parameter of a note limpness could also provide a standard for rejecting a note. With this new detection method of quantifying the limpness of a note, currency distributors would also have a tool for monitoring the average lifespan of notes in circulation by comparing limpness measurements with the date of initial circulation of notes processed.
The present invention provides various methods for determining the limpness of a note and, thereby, addressing the many needs for determining this physical characteristic.